Drought Stress Research Articles

Comprehensive analysis of drought tolerance in pure lines derived from half-diallel crosses of upland cotton (Gossypium hirsutum L.)

Drought has a significant impact on plants, affecting their growth, development and survival. This study focuses on evaluating the impact of drought stress, a significant abiotic factor, on the agronomic and fiber parameters of potential cotton (Gossypium hirsutum L.) lines with the aim of developing drought-tolerant varieties. The experiment involved two irrigation regimes—well-watered (100% field capacity) and deficit irrigation (50% field capacity)—conducted on F9–F10 generations. Key fiber parameters, including fiber length, boll weight, fiber strength, and lint percentage, were identified as crucial selection criteria under both well-watered and deficit irrigation conditions. Notably, boll number emerged as the decisive parameter in both F9 and F10 generations. The study employed univariate and multivariate analyses, such as PCA, heat map cluster, correlation analysis, and decision tree, which consistently highlighted fiber length, boll weight, fiber strength and lint (ginning) percentage the key factor. In the F10 generation, the integration of decision tree and heat map cluster results led to the identification of 8 promising lines. These selected genotypes have potential for inclusion in future cotton breeding programmes, offering the opportunity to increase drought tolerance and improve cotton yield and productivity. Their resilience to environmental stresses makes them promising candidates for improving overall cotton performance under challenging conditions.

Screening of New Dendrobium officinale Strains Adapted to Karst Forest Environmental Stress Based on Electrophysiological Detection Method

At present, the main methods of breeding Dendrobium officinale (D. officinale) include introduction and domestication, selective breeding, hybrid breeding, and mutation breeding. In the process, traditional methods of field investigation of agronomic traits are often used to select resistant varieties. Although these breeding methods are effective, they have a certain degree of subjectivity and empiricism, and the breeding cycle is long. Electrophysiological instruments were used in this experiment to test the material transport and metabolic capacity of D. officinale in a karst forest epiphytic environment and to quickly evaluate the suitability of different strains of D. officinale in a drought environment. These instruments detected the data on electrophysiological information of leaves of different strains of D. officinale under long-term drought conditions, providing immediate access to the inherent electrophysiological information of the leaves of these strains. Based on the electrophysiological parameters of D. officinale leaves as defined by the inherent electrophysiological information of plants, the water metabolism, nutrient transport, and metabolic capacity in different leaves were evaluated. The key electrophysiological indexes were verified by combining the results of chlorophyll fluorescence and chlorophyll content. The results indicate the following: (1) Parameters defined based on electrophysiological information effectively characterized the differences in intracellular water utilization, the nutrient transport status, and the metabolic capacity of different D. officinale strains. (2) The intrinsic physiological resistance, intrinsic physiological reactance, active nutrient transport capacity, and passive nutrient transport capacity were closely related to the growth status and chlorophyll function of D. officinale leaves. These electrophysiological parameters could serve as critical indicators for evaluating the drought resistance of D. officinale. (3) Under severe drought stress, strain LH1 exhibited less leaf damage, adequate water/nutrient supply, vigorous life activities, and excellent drought resistance. We found that strain LH1 demonstrates better adaptation to the arid environment of karst forest lands. The electrophysiological detection method employed in this study offers a new technique for screening wild-cultivated D. officinale resistance strains. The results indicate that the real-time online leaf electrophysiological information measured by the method in this study can characterize the energy and material metabolism of crops, greatly improving the efficiency of crop-variety selection and reducing costs. These conclusions can be used to obtain real-time information on the transmission of water and nutrients within plant cells and can provide theoretical support for studying the adaptation mechanisms of crops to adverse environments.

Effect of zeolite and irrigation treatments on grapevine leaves, an interdisciplinary approach

Abstract Aims Global warming depicts a real challenge for viticulture. As found by PubMed results, a 90% increase in the abiotic stress publications number from 2015 onwards is registered. Soil and grapevine response interaction to abiotic stress is arbitrated by an intricate signal transduction network that determines adaptive changes and modifications in gene expression mediated by the transcription factors (WRKY proteins). Briefly, (i) Does zeolite application affect canopy and biochemical leaf components? (ii) Is it possible to start a gene expression approach in an open-field vineyard, without fixed and stable external parameters obtaining an interconnected net of interdisciplinary data? (iii) Could the zeolite application be a corroborant tool to maintain a state of homeostasis in grapevine? Methods After a soil clinoptilolite treatment (the "Roca magica" well known as water moderator) and/or irrigation utilizing vines presented to drought and high sun exposure, we investigated leaf biochemical variations (proline, chlorophyll, and quercetins) and we analyzed with rt-PCR approach the expression of selected genes (VvWRKY47 and VvWRKY39). Results Lower water potential and leaf temperature were recorded in plants subjected to treatments against abiotic stress together with greater chlorophyll a, b, and less quercetin-3-O-glucoside. A down-regulation in VvWRKY47 gene and an up-regulation in VvWRKY39 gene were found. The VvWRKY47 showed interactions from the beginning with the zeolitic treatment. Conclusion The zeolite in our experiment acted as a water flywheel, mitigating the effects of climate change; plant-soil interactions were positively emphasized by clinoptilolite. Finally, results suggest that VvWRKY47 could be a valid candidate in the evaluation of drought and temperature stress in the open-field.

Effects of arbuscular mycorrhizal fungi in the rhizosphere of two olive (Olea europaea) varieties Arbequina and Barnea under water deficit conditions.

One strategy to improve olive (Olea europaea ) tree drought tolerance is through the symbiosis of arbuscular mycorrhizal fungi (AMF), which helps alleviate water deficit through a combination of morphophysiological effects. Cuttings of olive varieties Arbequina (A) and Barnea (B) were grown with (+AMF) or without (-AMF) inoculum in the olive grove rhizosphere soil. One year after establishment, pots were exposed to four different water regimes: (1) control (100% of crop evapotranspiration); (2) short-period drought (20days); (3) long-period drought (25days); and (4) rewatering (R). To evaluate the influence of AMF on tolerance to water stress, stem water potential, stomatal conductance and the biomarkers for water deficit malondialdehyde, proline, soluble sugars, phenols, and flavonoids were evaluated at the end of the irrigation regimes. Stem water potential showed higher values in A(+) and B(+) in all water conditions, and the opposite was true for stomatal conductance. For proline and soluble sugars, the stem water potential trend is repeated with some exceptions. AMF inoculum spore communities from A(+ and -) and B(+ and -) were characterised at the morphospecies level in terms of richness and abundance. Certain morphospecies were identified as potential drought indicators. These results highlight that the benefits of symbiotic relationships between olive and native AMF can help to mitigate the effects of abiotic stress in soils affected by drought.

Exon-Enriched Set of Single-Nucleotide Polymorphisms Shows Associations with Climate in European Beech (Fagus sylvatica L.)

European beech is an ecologically and commercially important species, which is expected to decline in several regions because of heat and drought stress associated with climate change. Knowledge of the genetic basis of the adaptation to climate is needed to guide assisted migration. Genetic variation at 1704 single-nucleotide polymorphisms (SNPs) resulting from ddRAD sequencing, primarily located in gene exons, was studied in 181 specimens representing 123 populations distributed over most of the whole range. Bayesian analysis of population structure yielded two clusters exhibiting a clear longitudinal cline and correlated with indicators of low temperatures and temperature fluctuation. Five SNPs were significantly associated with climatic variables related primarily to heat and temperature ranges. Two alternative explanations are offered for the observed response patterns: i) differential sensitivity to heat and ii) response mediated by vegetative phenology.

Metabolic Response of the Lycium barbarum Variety ‘Ningqi No. 7′ to Drought Stress

Lycium barbarum has been widely planted in arid and semi-arid areas due to its drought-resistant ability, which is of great economic value as a medicinal and edible homology plant. In this study, the metabolome of the L. barbarum variety “Ningqi 7” under different drought stress conditions was compared and analyzed by the non-targeted UPLC-MS (ultra-high performance liquid chromatography with mass spectrometry) technique. The results showed that drought stress significantly decreased the water content of leaves, increased the activity of antioxidant enzymes in plants, and up-regulated the metabolites and pathways involved in osmoregulation, antioxidant stress, energy metabolism, and signal transduction. Under moderate drought (40–45% FC), L. barbarum accumulated osmoregulatory substances mainly through the up-regulation of the arginine metabolism pathway. At the same time, phenylalanine metabolism and cutin, suberine, and wax biosynthesis were enhanced to improve the antioxidant capacity and reduce water loss. However, in severe drought (10–15% FC), L. barbarum shifted to up-regulate purine metabolism and lysine degradation and redistributed energy and nitrogen resources. In addition, vitamin B6 metabolism was significantly upregulated in both groups of stress levels, playing a key role in antioxidant and growth regulation. These observations delineate the metabolic adaptations of L. barbarum “Ningqi 7” in response to drought stress.

Exogenous application of plant bio-regulators improve yield and water use efficiency of maize under drought stress

Moisture stress in rainfed areas has significant adverse impact on plant growth and yield. Exogenous application of plant bio-regulators (PBRs) plays an important role to mitigate drought stress in plants. A field experiment was conducted during rainy (kharif) seasons of 2018 and 2019 to explore the positive role of PBRs on the yield, economic feasibility and water use efficiency of maize grown under rainfed conditions. Ten treatments including PBRs, mulching and control were evaluated in a randomized block design. The result showed that foliar spray of salicylic acid (0.5 mM) with 1% urea solution improved the grain yield of maize by 24% as compared to control plot. Other PBRs such as glycine betaine, gibberellic acid and thiourea also increased the grain yield in the range of 10–21%. Application of 1% urea solution with PBRs synergise the effect of PBR to alleviate drought stress. The foliar applied PBRs maintained higher membrane stability index (73–78%), significantly increased relative water content (5–11%), chlorophyll content and decreased the proline content (11–21%) as compared to plants grown in control plot. Significant increase were noted in the rain and crop water use efficiency of maize with the foliar application of PBRs. Net returns were improved by 33% with application of salicylic acid (0.5 mM) + 1% urea as compared to control (₹49 × 103 /ha). Thus, foliar spray of salicylic acid (0.5 mM) with 1% urea solution could be an economic feasible strategy to reduce the adverse effects of drought and may increase the maize yield and water use efficiency.

Yield Trait and Stability of Chickpea Genotypes for Intensification of Drought‐Prone Rice Fallows of South Asia

ABSTRACTThere is a need for increasing cropping intensity in South Asia including India to ensure food security of burgeoning population. Accordingly, increasing cropping intensity in rainfed rice fallows can be a futuristic strategy. Identification of suitable cultivar and exploration of genetic variability of specific crops/traits are imperative for genetic improvement, drought resistance and yield gain in rice fallows. We evaluated the morphophysiological, yield traits and stability of 15 chickpea genotypes in randomised complete block design for three consecutive years on a drought‐prone rainfed condition of Fluvisol in Kanpur, India. Among genotypes, ‘IPC 2014‐55’, ‘IPC 2015‐44’ and ‘IPC 2011‐92’ had 2%–10% higher relative water content (RWC) over ‘ICC‐92944’ (check cultivar). These genotypes did not differ for total chlorophyll content, root dry weight and nodule dry weight with ‘ICC‐92944’ and ‘KWR 108’ (wider adaptable cultivar of the region). The nitrogen balance index was higher in ‘IPC 2011‐92’, ‘IPC 2014‐88’ and ‘IPC 2014‐55’ by 5%–44% over check cultivar (p < 0.05). The membrane stability index was higher for ‘IPC 2014‐55’ (30%, p < 0.05) and ‘IPC 2011‐92’ (17%, p < 0.05) than ‘ICC‐92944’. ‘IPC 2011‐92’, ‘IPC 2014‐88’ and ‘IPC 2014‐55’ (3 years mean) had 3%–24% higher plant dry weight than ‘ICC‐92944’. Notably, ‘IPC 2014‐55’, ‘IPC 2015‐44’, ‘IPC 2014‐88’ and ‘IPC 2011‐92’ had higher yield attributes such as pods plant−1 by 9%, grain weight plant−1 by 13% and 100‐seed weight by 3% than ‘ICC‐92944’ and ‘KWR 108’ (mean of years). These genotypes had higher mean seed yield than ‘ICC‐92944’ by 23%–42% and ‘KWR 108’ by 7%–23% (p < 0.05). The yield of ‘IPC 2014‐55’, ‘IPC 2015‐44’, ‘IPC 2014‐88’ and ‘IPC 2011‐92’ were stable over years across variable soil and environmental condition as indicated by the genotype × year biplot. Membrane stability index, pods plant−1 and 100‐seed weight were the determinants for increased seed yield of chickpea under drought‐prone condition. Evidently, genotype ‘IPC 2014‐55’, ‘IPC 2015‐44’, ‘IPC 2014‐88’ and ‘IPC 2011‐92’ were better under rainfed rice fallows. These genotypes could be tested under specific drought condition for developing varieties and promoted in rice fallows of South Asia for yield advantage and drought resistance.

Promoter of Cassava MeAHL31 Responds to Diverse Abiotic Stresses and Hormone Signals in Transgenic Arabidopsis

The AT-hook motif nuclear-localized (AHL) family is pivotal for the abiotic stress response in plants. However, the function of the cassava AHL genes has not been elucidated. Promoters, as important regulatory elements of gene expression, play a crucial role in stress resistance. In this study, the promoter of the cassava MeAHL31 gene was cloned. The MeAHL31 protein was localized to the cytoplasm and the nucleus. qRT-PCR analysis revealed that the MeAHL31 gene was expressed in almost all tissues tested, and the expression in tuber roots was 321.3 times higher than that in petioles. Promoter analysis showed that the MeAHL31 promoter contains drought, methyl jasmonate (MeJA), abscisic acid (ABA), and gibberellin (GA) cis-acting elements. Expression analysis indicated that the MeAHL31 gene is dramatically affected by treatments with salt, drought, MeJA, ABA, and GA3. Histochemical staining in the proMeAHL31-GUS transgenic Arabidopsis corroborated that the GUS staining was found in most tissues and organs, excluding seeds. Beta-glucuronidase (GUS) activity assays showed that the activities in the proMeAHL31-GUS transgenic Arabidopsis were enhanced by different concentrations of NaCl, mannitol (for simulating drought), and MeJA treatments. The integrated findings suggest that the MeAHL31 promoter responds to the abiotic stresses of salt and drought, and its activity is regulated by the MeJA hormone signal.

Unveiling Genotypic Response of Chickpea to Moisture Stress Based on Morpho‐Physiological Parameters in the Eastern Indo‐Gangetic Plains

ABSTRACTIn the eastern Indo‐Gangetic plains, chickpea is grown postrice cultivation mostly under rainfed condition with residual soil moisture which adversely affects branching as well as pod and seed development, ultimately resulting in substantial yield losses. The current study analysed the moisture stress response of 12 chickpea genotypes with control for different morpho‐physiological traits in two sets of field experiments carried out during the year 2017–18 and 2018–19. The current study observed varying response of chickpea genotypes under moisture stress condition with average yield reduction from 11.79% to 24.77%. Mean yield of genotypes under stress condition showed a strong positive association with yield index (1.00**) and stress tolerance index (0.915**). The biplot principal component analysis revealed maximum potential of three chickpea genotypes (DBGC 1, Pusa 256 and DBGC 2) for grain yield and biological yield under moisture stress condition. The correlation analysis showed a significant association of yield with physiological parameters such as photosynthetic rate (0.363**), stomatal conductance (0.364**) and transpiration rate (0.292*). The three higher yielding genotypes relatively maintained biological yield, yield plant−1, 100 seed weight and photosynthesis rate and showed reduced rates of stomatal conductance and transpiration under moisture stress condition. The study found variable genotypic response to moisture stress and showed that yield index as well as stress tolerance index was more effective to identify superior genotypes for moisture stress condition. The superior genotypes identified in the present study may be considered for rainfed areas of eastern Indo‐Gangetic plains and can be used in future chickpea breeding programs for drought tolerance.

Physiological, biochemical and hormonal response of wheat cultivars to foliar application of growth stimulants and zinc nano-chelate under water deficit stress

To investigate the effect of different foliar application treatments to improve drought tolerance in wheat genotypes, a factorial split-plot experiment was conducted based on the randomized complete block design with 3 replications in 2 locations. The main factor was irrigation (normal and water deficit) and the secondary factors were 4 levels of foliar application (control: without foliar application, jasmonic acid, zinc nano-chelate and succinate) and 3 genotypes of barley. Water deficit stress reduced the content of chlorophyll a (9.03%), chlorophyll b (6.66%), total chlorophyll (7.32%) and auxin (4.21%) and increased the catalase (18.18%), superoxide dismutase activity (23.35%), malondialdehyde (7.17%), glucose (5.35%), fructose (4.85%) and sucrose (14.99%) versus normal irrigation conditions. Foliar application of zinc nano-chelate increased chlorophyll a, chlorophyll b, total chlorophyll and fructose content by 15.45%, 15.76%, 14.70% and 41.35% respectively. The highest content of chlorophyll a, chlorophyll b and total chlorophyll was assigned to the Mihan cultivar. Foliar application with zinc nano-chelate in both environments resulted in the highest biological yield and grain yield and the lowest content of abscisic acid. Foliar application line 9 genotypes with zinc nano-chelate had the highest auxin, cytokinin, catalase and superoxide dismutase activity. While foliar application of nano-zinc chelate in the Mihan cultivar led to the highest biological yield, grain yield, glucose content and the lowest amount of malondialdehyde. Therefore, foliar application of zinc nano-chelate along with the appropriate variety can improve grain yield under different environmental conditions.

Stress-induced nuclear translocation of ONAC023 improves drought and heat tolerance through multiple processes in rice

Drought and heat are major abiotic stresses frequently coinciding to threaten rice production. Despite hundreds of stress-related genes being identified, only a few have been confirmed to confer resistance to multiple stresses in crops. Here we report ONAC023, a hub stress regulator that integrates the regulations of both drought and heat tolerance in rice. ONAC023 positively regulates drought and heat tolerance at both seedling and reproductive stages. Notably, the functioning of ONAC023 is obliterated without stress treatment and can be triggered by drought and heat stresses at two layers. The expression of ONAC023 is induced in response to stress stimuli. We show that overexpressed ONAC23 is translocated to the nucleus under stress and evidence from protoplasts suggests that the dephosphorylation of the remorin protein OSREM1.5 can promote this translocation. Under drought or heat stress, the nuclear ONAC023 can target and promote the expression of diverse genes, such as OsPIP2;7, PGL3, OsFKBP20-1b, and OsSF3B1, which are involved in various processes including water transport, reactive oxygen species homeostasis, and alternative splicing. These results manifest that ONAC023 is fine-tuned to positively regulate drought and heat tolerance through the integration of multiple stress-responsive processes. Our findings provide not only an underlying connection between drought and heat responses, but also a promising candidate for engineering multi-stress-resilient rice.

TaMYB44-5A reduces drought tolerance by repressing transcription of TaRD22-3A in the abscisic acid signaling pathway.

TaMYB44-5A identified as a transcription factor negatively regulates drought tolerance in transgenic Arabidopsis. Drought can severely reduce yields throughout the wheat-growing season. Many studies have shown that R2R3-MYB transcription factors are involved in drought stress responses. In this study, the R2R3-MYB transcription factor MYB44-5A was identified in wheat (Triticum aestivum L.) and functionally analyzed. Three homologs of TaMYB44 were isolated, all of which localized to the nucleus. Overexpression of TaMYB44-5A reduced drought tolerance in Arabidopsis thaliana. Further analysis showed that TaMYB44-5A reduced the sensitivity of transgenic Arabidopsis to ABA. Genetic and transcriptional regulation analyses demonstrated that the expression levels of drought- and ABA-responsive genes were downregulated by TaMYB44-5A, and TaMYB44-5A directly bound to the MYB-binding site on the promoter to repress the transcription level of TaRD22-3A. Our results provide insights into a novel molecular pathway in which the R2R3-MYB transcription factor negatively regulates ABA signaling in response to drought stress.

Study of Drought Resistance of New Varieties of Spring Barley Based on Photosynthetic Potential and Leaf Diagnostics “Ecotest 2020” in Arid Conditions of the Lower Volga Region

Study of Drought Resistance of New Varieties of Spring Barley Based on Photosynthetic Potential and Leaf Diagnostics “Ecotest 2020” in Arid Conditions of the Lower Volga Region

Forest growth resistance and resilience to the 2018–2020 drought depend on tree diversity and mycorrhizal type

Abstract The frequency of consecutive drought years is predicted to increase due to climate change. These droughts have strong negative impacts on forest ecosystems. Mixing tree species is proposed to increase the drought resistance and resilience of tree communities. However, this promising diversity effect has not yet been investigated under extreme drought conditions and in the context of complementary mycorrhizal associations and their potential role in improving water uptake. Here, we investigate whether tree diversity promotes growth resistance and resilience to extreme drought and whether drought responses are modulated by mycorrhizal associations. We used inventory data (2015–2021) from a young tree diversity experiment in Germany, manipulating tree species richness (1, 2 and 4 species) and mycorrhizal type (communities containing arbuscular mycorrhizal [AM] or ectomycorrhizal [EM] tree species, or both). For all tree communities, we calculated basal area increment in the periods before, during and after drought and used the concepts of resistance and resilience to quantify growth responses to drought. We found strong growth declines during the extreme 2018–2020 drought for most tree communities. Contrary to our hypothesis, we did not find that tree species richness per se can buffer the negative impacts of extreme drought on tree growth. However, while for EM communities, drought resistance and resilience decreased with tree species richness, they increased for AM communities and communities comprising both mycorrhizal types. We highlight that among various mixtures of tree species, only those with mixed mycorrhizal types outperformed their respective monocultures during and after drought. Furthermore, under extreme drought, the community tends to segregate into ‘winner’ and ‘loser’ tree species in terms of diversity, indicating a possible intensification of competition. While we cannot disentangle the underlying mechanisms or clarify the role of mycorrhiza during drought, our findings suggest that mixtures of mycorrhizal types within tree communities could help safeguard forests against increasing drought frequency. Synthesis. Drought resistance and resilience of tree communities depend on tree diversity and mycorrhizal association types. Mixing tree species with diverse mycorrhizal types holds promise for forest restoration in the face of climate change.

Molecular characterization and evaluation of different irrigation regimens on yield and other agronomic traits of some Egyptian wheat cultivars

ABSTRACT The objective of this study was to determine the optimal irrigation needs of six popular Egyptian bread wheat (Triticum aestivum L.) cultivars and to establish baseline effect of reduced irrigation on yield. The varieties included were Sids1, Sids14, Sakha94, Sakha95, Gemmiza12, and Shandawee1. The experiment was conducted at two different locations, Nubaria and Sids Agricultural Research Stations, Egypt over two consecutive seasons, 2020–2021 and 2021–2022. There was a reduction in yield with the decrease in the number of irrigations. However, several cultivars performed better for yield and other traits with one less irrigation than the current irrigation practices in the region. Therefore, the study may help revise irrigation recommendations. Overall, the cultivars Sakha95, Sids1, and Sids14 were taller and had more kernels per spike, higher seed index, and greater grain yield under reduced irrigations and showed the best drought tolerance index. The tested bread wheat cultivars were genotyped using Inter-Retrotransposon Amplified Polymorphism (IRAP) and Start Codon Targeted (SCoT) markers which showed relation among the cultivars. Among the two types of markers, IRAP was better than SCoT markers for reliability and robustness. Among the six cultivars, 58% of the IRAP markers detected polymorphism as compared to 38% with SCoT markers. The two wheat cultivars Sids1 and Sids14, which performed better for important agronomic traits under water stress conditions, could be used as donors for the national wheat breeding program for drought tolerance.

Screening and Verification of Aquaporin Gene AsPIP1-3 in Garlic (Allium sativum L.) under Salt and Drought Stress

Screening and Verification of Aquaporin Gene AsPIP1-3 in Garlic (Allium sativum L.) under Salt and Drought Stress

Glycosylation mode of phloretin affects the morphology and stress resistance of apple plant.

Phloretin has different glycosylation modes in plants. Phlorizin (phloretin 2'-O-glucoside) is one of the glycosylation products of phloretin, and accumulates abundantly in apple plants. However, it is still unclear whether phlorizin is more beneficial for apple plants compared with other glycosylation products of phloretin. We created transgenic apple plants with different glycosylation modes of phloretin. In transgenic plants, the accumulation of phlorizin was partly replaced by that of trilobatin (phloretin 4'-O-glucoside) or phloretin 3',5'-di-C-glycoside. Compared with wild type, transgenic plants with less phlorizin showed dwarf phenotype, larger stomatal size, higher stomatal density and less tolerance to drought stress. Transcriptome and phytohormones assay indicate that phlorizin might regulate stomatal development and behaviour via controlling auxin and abscisic acid signalling pathways as well as carbonic anhydrase expressions. Transgenic apple plants with less phlorizin also showed less resistance to spider mites. Apple plants may hydrolyse phlorizin to produce phloretin, but cannot hydrolyse trilobatin or phloretin 3',5'-di-C-glycoside. Compared with its glycosylation products, phloretin is more toxic to spider mites. These results suggest that the glycosylation of phloretin to produce phlorizin is the optimal glycosylation mode in apple plants, and plays an important role in apple resistance to stresses.

Enhancing drought tolerance in Malva parviflora plants through metabolic and genetic modulation using Beauveria bassiana inoculation

BackgroundEnhancing crops’ drought resilience is necessary to maintain productivity levels. Plants interact synergistically with microorganisms like Beauveria bassiana to improve drought tolerance. Therefore, the current study investigates the effects of biopriming with B. bassiana on drought tolerance in Malva parviflora plants grown under regular irrigation (90% water holding capacity (WHC)), mild (60% WHC), and severe drought stress (30% WHC).ResultsThe results showed that drought stress reduced the growth and physiological attributes of M. parviflora. However, those bioprimed with B. bassiana showed higher drought tolerance and enhanced growth, physiological, and biochemical parameters: drought stress enriched malondialdehyde and H2O2 contents. Conversely, exposure to B. bassiana reduced stress markers and significantly increased proline and ascorbic acid content under severe drought stress; it enhanced gibberellic acid and reduced ethylene. Bioprimed M. parviflora, under drought conditions, improved antioxidant enzymatic activity and the plant’s nutritional status. Besides, ten Inter-Simple Sequence Repeat primers detected a 25% genetic variation between treatments. Genomic DNA template stability (GTS) decreased slightly and was more noticeable in response to drought stress; however, for drought-stressed plants, biopriming with B. bassiana retained the GTS.ConclusionUnder drought conditions, biopriming with B. bassiana enhanced Malva’s growth and nutritional value. This could attenuate photosynthetic alterations, up-regulate secondary metabolites, activate the antioxidant system, and maintain genome integrity.

Integrating high-throughput phenotyping and genome-wide association studies for enhanced drought resistance and yield prediction in wheat.

Drought, especially terminal drought, severely limits wheat growth and yield. Understanding the complex mechanisms behind the drought response in wheat is essential for developing drought-resistant varieties. This study aimed to dissect the genetic architecture and high-yielding wheat ideotypes under terminal drought. An automated high-throughput phenotyping platform was used to examine 28 392 image-based digital traits (i-traits) under different drought conditions during the flowering stage of a natural wheat population. Of the i-traits examined, 17 073 were identified as drought-related. A genome-wide association study (GWAS) identified 5320 drought-related significant single-nucleotide polymorphisms (SNPs) and 27 SNP clusters. A notable hotspot region controlling wheat drought tolerance was discovered, in which TaPP2C6 was shown to be an important negative regulator of the drought response. The tapp2c6 knockout lines exhibited enhanced drought resistance without a yield penalty. A haplotype analysis revealed a favored allele of TaPP2C6 that was significantly correlated with drought resistance, affirming its potential value in wheat breeding programs. We developed an advanced prediction model for wheat yield and drought resistance using 24 i-traits analyzed by machine learning. In summary, this study provides comprehensive insights into the high-yielding ideotype and an approach for the rapid breeding of drought-resistant wheat.